The speed limit on South Duff Avenue may be lowered once again after the Ames City Council submitted a request to the Iowa Department of Transportation.

Originally, the speed limit on the road was set at 50 miles per hour. In 1999, complaints from residents persuaded the DOT to lower the speed limit to 40 miles per hour as far south as Airport Road, said Ames Police Chief Dennis Ballantine. The rest of the road heading outside of Ames is set at 45 miles per hour.

Currently, those living in the Southdale residential area are pushing for another reduction in the posted speed limits in the area south of Highway 30 and east of the airport, said Bob Kindred, assistant city manager.

“South Duff is part of U.S. Highway 69, which continues on to Lincoln Way, west to Grand Avenue and north out of town,” Kindred said. “Because it is a federal highway, the Iowa DOT is responsible for maintaining it and deciding what the speed limits are going to be.”

The city council spoke to DOT officials again about the speed limit Nov. 14.

“Residents were expressing concerns of turning traffic,” Ballantine said. “They believed the speed of the cars created a safety hazard.”

DOT officials responded by saying they would lower the speed limit on South Duff Avenue to as low as 35 miles per hour as long as the city would agree to provide enforcement to keep people from disregarding the new limit, Kindred said.

“The city council decided that it probably wouldn’t work to force people to drive slower than they feel safe. Some people would see the 35-mile-per-hour signs and slow down, while others would say ‘I feel safe driving faster, so I’m not going to slow down,'” Kindred said.

Speed limits are set at the speed which 85 percent of people drive at or below, said Paul Wiegand, public works director.

He said the 85th percentile on South Duff between Highway 30 and the Squaw Creek Bridge is currently 50 miles per hour, which corresponds with the speed limit for that area. If the city is willing to do more enforcing, the DOT would agree to lower the limit to the 50th percentile, which is 45 miles per hour.

The city council declined the DOT’s offer to reduce the limit and require an increase in enforcement. There are currently no plans to reduce the speed limit, Ballantine said. However, the city council has not given up hope on a lower limit.

“We’ve written back to the DOT to see if they would consider a reduction to 40 miles per hour,” Kindred said.

Before they approve a reduction in the speed limit, the DOT will continue collecting information about the flow of traffic on South Duff.